Abstract: According to the investigation on the cadmium contents in Crassostrea gigas, Perna viridis, Meretrix meretrix and Ruditapes philippinarum from Guangdong and Guangxi of China in 2009, we assessed the dietary exposure to cadmium by probabilistic assessment based on Monte Carlo simulation, and conducted a quantitative analysis of the uncertainty and variability of the evaluation. The cadmium contents of all samples in the investigation sea area, which are significantly different, are lower than the concentration limit of certain hazardous substances for harmless aquatic products. The estimated dietary exposure to cadmium is lower than the provisional tolerable weekly intake (PTWI) of cadmium recommended by Joint Expert Committee on Food Additives (JECFA) of FAO/WHO, but accounts for very great proportion of PTWI at the level of P95 percentage. It is suggested that dietary exposure to cadmium be reduced by relevant measures.